System for actuating a two part mould forming two mutually articulated half-moulds

ABSTRACT

The invention concerns a system for actuating a two-part mould ( 1 ) forming two half-moulds ( 1, 1 ) mutually articulated about a shaft ( 2 ) forming a hinge and driven, between an opening position and a closing position, by a translational carriage ( 7 ) driven in a reciprocating movement. The inventive system is particularly characterised in that each half-mould ( 1, 1 ) is further articulated on a part ( 4   a,    4   b ) which pivots about a shaft ( 5   a,    5   b ) and which is driven in rotation by at least an actuating link rod ( 6   a,    6   b ) articulated through its ends respectively to said pivoting part ( 4   a,    4   b ) and to said translational carriage ( 7 ).

[0001] The invention relates to an actuation system for a mould in twoparts forming two half-moulds articulated about an axis forming a hinge.

[0002] It is known how to make moulds in two parts or half-moulds,particularly for injection moulding and blowing moulding machines.

[0003] Each of the two half-moulds is usually mounted on a carriage, andthey are moved towards each other while remaining parallel to eachother.

[0004] Systems in which the two-half moulds are articulated about anaxis forming a hinge and controlled between an open position and aclosed position by a trolley free to move in translation in aforward-backward movement, as described in French patent 2 059 446 and 2088 523 and in application FR-2 793 722, have also been known for a longtime.

[0005] The invention relates to a system for the actuation of a two-partmould forming two-half moulds of the type mentioned above, but which isremarkable in that each half-mould is also articulated on a part thatpivots about an axis and that is moved in rotation by at least oneactuation rod articulated by its ends to the said pivoting part and tothe said carriage free to move in translation respectively.

[0006] According to one embodiment, each half-mould is articulated onthe pivoting part by at least one connecting rod, whereas the actuationrods for the pivoting parts of the half-moulds are articulated on acommon translation carriage, and more particularly in the latter case,the translation carriage is for example composed of a cross piece thatis installed free to slide on at least two rails and on which theactuation connecting rods are articulated.

[0007] Preferably, the translation carriage is moved forwards andbackwards by at least one roller that cooperates with a cam and, forexample, the roller may be placed on a connecting rod installed so as topivot about an axis fixed with respect to the pivoting axes of thepivoting parts activating the half-mould.

[0008] Advantageously, when the half-moulds are in the closed position,the longitudinal axes of the connecting rods installed between the saidhalf-moulds and the pivoting parts are approximately in line with eachother along the line joining the pivoting axes of the said pivotingparts.

[0009] Due to this arrangement, the half-moulds are naturally locked toeach other when in the closed position without any other complementarymeans.

[0010] The invention also relates to a set of moulds each provided withan actuation system like that mentioned above, this assembly beingremarkable in that the moulds are arranged in a circle or along the arcof a circle and in that the translation carriages are moved by rollersthat cooperate with a common cam, the said moulds moving relative to thecam.

[0011] According to one embodiment, the moulds are fixed on an elementthat rotates about the common cam that is fixed in position, but itcould also be imagined that the moulds could be fixed and the cam couldbe moved in a rotary movement.

[0012] The invention will be better understood after reading thefollowing description with reference to the attached drawings in which:

[0013]FIGS. 1 and 2 show a perspective view of a system according to theinvention, the mould being shown in the open and closed positionsrespectively;

[0014]FIGS. 3 and 4 show a top view of the systems in FIGS. 1 and 2respectively, also partly showing the actuation cam;

[0015]FIG. 5 is a top view of a set of several moulds each provided withan actuation system controlled by a common cam.

[0016] As shown on the drawings, the system according to the inventionwill actuate a mould 1 in two parts forming two half-moulds 1′, 1″articulated to each other about an axis 2 forming a hinge.

[0017] Each half-mould 1′, 1″ is articulated through a connecting rod 3a, 3 b on a part 4 a, 4 b that is installed free to pivot about an axis5 a, 5 b.

[0018] The pivoting parts 4 a, 4 b are each moved in rotation by anactuation rod 6 a, 6 b articulated by its ends to the said part 4 a, 4 brespectively and to a translation carriage 7.

[0019] The carriage 7 consists of a cross piece that is installed freeto slide on two rails 8 a, 8 b, and on which one of the ends of theactuation rods 6 a, 6 b is articulated.

[0020] In this way, it can be understood that with a forward-backwardmovement of the carriage 7, the assembly moves from the open position inFIGS. 1 and 3 to the corresponding closed position in FIGS. 2 and 4 andvice versa.

[0021] Translation of the carriage 7 causes pivoting of parts 4 a, 4 b,by means of the connecting rods 6 a, 6 b, and thus closes and then opensthe moulds through the action of the connecting rods 3 a, 3 b on thehalf-moulds 1′, 1″, the pivoting axes 2, 5 a and 5 b being fixed withrespect to the movement of the carriage 7.

[0022] An articulating push and pull rod 9 is provided fixed firstly tothe said carriage and secondly to a connecting rod 10 free to pivotabout an axis 11 and provided with a roller 12 in order to move thecarriage 7, the axis 11 being fixed with respect to axes 5 a, 5 b aboutwhich parts 4 a, 4 b pivot.

[0023] The roller 12 cooperates with a cam 13 shown partially in FIGS. 3and 4.

[0024] Depending on the position of the roller 12 on the cam 13, it canbe seen that the mould may be open (FIG. 3) or closed (FIG. 4), sincethe roller follows the path shown in 14 in FIGS. 3 and 4.

[0025] The roller 12 and the cam 13 must have a relative movement withrespect to each other. For example, the cam 13 moves with respect to thesupport of mould 1 formed by the axes 5 a, 5 b and 2 which are thenfixed, or more particularly the entire mould and its actuation systemmove with respect to the cam 13 which is then fixed.

[0026] As shown in particular in FIGS. 2 and 4, in the closed positionthe longitudinal axes of the connecting rods 3 a, 3 b are approximatelyin line with each other along the line between the pivot axes 5 a, 5 bof the pivoting parts 4 a, 4 b, or the said axes 5 a, 5 b areapproximately in the same plane as the plane containing the articulationaxes of the connecting rods 3 a, 3 b.

[0027] In this position, the articulation axes of the connecting rods 3a, 3 b with the pivoting parts 4 a, 4 b may be slightly beyond the lineconnecting the pivot axes 5 a, 5 b.

[0028] In this way, the mould is held partly locked by the pressureapplied by the carriage, but also by the geometry of the system thatopposes opening without deliberate backward movement of the carriage 7.

[0029]FIG. 5 shows a set of twelve moulds la to 11 each provided with anactuation system like that described with reference to FIGS. 1 to 4, andfor example this assembly being used to blow hollow bodies such asbottles, from thermoplastic preforms.

[0030] Moulds 1 a to 11 are arranged as shown in FIG. 5, around a circleat the centre of which there is a common cam 13, in this case fixed.

[0031] The previously described pivot axes references 2, 5 a, 5 b, andthe pivot axes 11 of the connecting rods 10, and obviously also therails 8 a, 8 b on which the carriages 7 are free to move, are fixed, forexample on a plate not shown that is free to rotate with respect to thecam 13 (although obviously, it would be possible to imagine a mobile camand fixed moulds).

[0032] The shape of the cam is designed and chosen so that one orseveral moulds open (1 a, 1 b) or close (1 c to 11) as shown in the saidFIG. 5, as a function of the angular position of the cam 13.

1. Actuation system for a mould (1) in two parts forming two half-moulds(1′,1″) articulated to each other about an axis (2) forming a hinge andcontrolled between an open position and a closed position through atranslation carriage (7) moved in a forward-backward movement,characterized in that each half-mould (1′, 1″) is also articulated on apart (4 a, 4 b) that pivots around an axis (5 a, 5 b) and that is movedin rotation by at least one actuation rod (6 a, 6 b) articulated by itsends to the said pivoting part (4 a, 4 b) and the said translationcarriage (7) respectively.
 2. Actuation system according to claim 1,characterized in that each half-mould (1′, 1″) is articulated to thepivoting part (4 a, 4 b) by means of at least one connecting rod (3 a, 3b).
 3. Actuation system according to any one of claims 1 and 2,characterized in that the actuation rods (6 a, 6 b) of the pivotingparts (4 a, 4 b) of the half-moulds (1′, 1″) are articulated on a commontranslation carriage (7).
 4. Actuation system according to claim 3,characterized in that the translation carriage (7) is composed of across piece that is installed free to slide on at least two rails (8 a,8 b) and on which the actuation rods (6 a, 6 b) are articulated. 5.Actuation system according to one of claims 1 to 4, characterized inthat the translation carriage (7) is moved forwards-backwards by atleast one roller (12) that cooperates with a cam (13).
 6. Actuationsystem according to claim 5, characterized in that the roller (12) isarranged on a rod (10) installed free to pivot about an axis (11) fixedwith respect to the pivot axes (5 a, 5 b) of the pivoting parts (4 a, 4b) actuating the half-moulds (1′, 1″).
 7. Actuation system according toone of claims 2 to 6, characterized in that in the closed position ofthe half moulds (1′, 1″), the longitudinal axes of the connecting rods(3 a, 3 b) installed between the said half-moulds (1′, 1″) and thepivoting parts (4 a, 4 b) are approximately in line with each otheralong the line connecting the pivot axes (5 a, 5 b) of the said pivotingparts (4 a, 4 b).
 8. Set of moulds (1 a, 11) each formed of twohalf-moulds articulated about an axis forming a hinge and each providedwith an actuation system according to any one of claims 1 to 7,characterized in that the moulds (1 a, 11) are arranged in a circle oralong the arc of a circle and in that the translation carriages aremoved by rollers that cooperate with a common cam (13), the said mouldbeing moved relative to the cam (13).
 9. Set of moulds according toclaim 8, characterized in that the moulds (1 a, 11) are fixed on anelement that rotates about the common cam (13) that is fixed inposition.